scholarly journals The Sound of Silence: Mouse Models for Hearing Loss

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sumantra Chatterjee ◽  
Thomas Lufkin
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Hearing Impairment ◽  
Economic Loss ◽  
Signaling Cascades ◽  
Otic Vesicle ◽  
New Genes ◽  
Personal Loss ◽  
The Individual

Sensorineural hearing loss is one of the most common disabilities in humans. It is estimated that about 278 million people worldwide have slight to extreme hearing loss in both ears, which results in an economic loss for the country and personal loss for the individual. It is thus critical to have a deeper understanding of the causes for hearing loss to better manage and treat the affected individuals. The mouse serves as an excellent model to study and recapitulate some of these phenotypes, identify new genes which cause deafness, and to study their roles in vivo and in detail. Mutant mice have been instrumental in elucidating the function and mechanisms of the inner ear. The development and morphogenesis of the inner ear from an ectodermal layer into distinct auditory and vestibular components depends on well-coordinated gene expression and well-orchestrated signaling cascades within the otic vesicle and interactions with surrounding layers of tissues. Any disruption in these pathways can lead to hearing impairment. This review takes a look at some of the genes and their corresponding mice mutants that have shed light on the mechanism governing hearing impairment (HI) in humans.

Self-Management of Hearing Impairment

2017 ◽  
pp. 340-359
Author(s):  
Lucy Handscomb ◽  
Gabrielle H. Saunders ◽  
Derek J. Hoare
Keyword(s):  
Decision Making ◽  
Hearing Loss ◽  
Health Behaviors ◽  
Hearing Impairment ◽  
Social Participation ◽  
Self Management ◽  
The Individual ◽  
Inform Decision Making

Hearing impairment is defined as hearing loss that leads to difficulties in hearing, or deafness, and affects an estimated 360 million people worldwide. Consequences of hearing impairment include difficulties in communication, restricting social participation, and leading to feelings of isolation. Hearing impairment cannot be cured, but its consequences can be reduced with self-management whereby the individual adopts, refines, and maintains health behaviors, supported through the provision and availability of suitable interventions. The barriers to self-management are many and should be explored to inform decision-making between the clinician and the individual with hearing impairment. The clinician can then facilitate self-management that is informed, realistic, and fully reflects the preferences and values of the individual.

Perceived Hearing Handicap of Patients with Unilateral or Mild Hearing Loss

1997 ◽  
Vol 106 (3) ◽  
pp. 210-214 ◽  
Author(s):  
Craig W. Newman ◽  
Gerald A. Hug ◽  
Gary P. Jacobson ◽  
Sharon A. Sandridge
Keyword(s):  
Hearing Loss ◽  
Individual Differences ◽  
Hearing Impairment ◽  
Pure Tone ◽  
Hearing Level ◽  
Intersubject Variability ◽  
Pure Tone Average ◽  
Hearing Handicap ◽  
Mild Hearing Loss ◽  
The Individual

Using the Hearing Handicap Inventory for Adults (HHIA), we assessed self-perceived hearing handicap in a sample of 63 patients having either unilaterally normal hearing or a mild hearing loss (pure tone average ≤40 dB hearing level). Large intersubject variability in responses to the HHIA confirmed observations that reactions to minimal hearing impairment vary greatly among patients. The individual differences in responses highlight the importance of quantifying the perceived communication and psychosocial handicap, which cannot be determined from the audiogram alone. An item examination of responses to the HHIA revealed a number of emotional and social-situational problems encountered by patients with minimal hearing loss.

Neuro-axonal recruitment: A result of selective compression

1990 ◽  
Vol 104 (3) ◽  
pp. 185-190 ◽  
Author(s):  
Ernst Lehnhardt
Keyword(s):  
Multiple Sclerosis ◽  
Hearing Loss ◽  
Inner Ear ◽  
Hearing Impairment ◽  
Auditory Nerve ◽  
Myelin Sheaths ◽  
Acoustic Neurinomas ◽  
Tone Decay ◽  
Interpeak Latency ◽  
Small Acoustic Neuroma

AbstractMany acoustic neurinomas and CPA tumours present an audiometric picture of positive-recruitment hearing impairment although often the CMs are not significantly impaired (according to ECochG) and because, even in the case of a small acoustic neuroma, the interpeak latency between wave I and V (ERA) is increased in the majority of cases. Recruitment cannot be explained, in these cases, as an expression of an accompanying vascular inner ear lesion. Therefore, we attempt to interpret the differential audiometric picture to the various patterns of damage of the auditory nerve. The finding of tone decay is seen as an expression of myelin damage corresponding to the hearing loss in multiple sclerosis.The absence of any degree of tone decay excludes an isolated damage of the myelin sheaths; hearing loss then results from a disturbance also of the associated axons. At such a stage, where there is a functional loss to part of the neural fibres but with intact myelinated residual fibres, the result could be the phenomenon of recruitment for suprathreshold stimulation. This theory of selective compression is compared to an isolated efferent lesion theory as the cause for recruitment in AN and CPA tumours.

scholarly journals Efficiency of a Dexamethasone Nanosuspension as an Intratympanic Injection for Acute Hearing Loss

2021 ◽  
Author(s):  
So-Young Jung ◽  
Zion Kang ◽  
Soonmin Kwon ◽  
Juhye Lee ◽  
Subin Kim ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Round Window ◽  
Round Window Membrane ◽  
In Vivo Test ◽  
Drug Concentrations ◽  
Intratympanic Injection ◽  
Acute Hearing Loss

Abstract Background: Dexamethasone sodium phosphate (Dex-SP) is the most commonly used drug for intratympanic injection in acute hearing loss, but its penetration efficiency into the inner ear is very low. To address this problem, we evaluated the possibility of dexamethasone nanosuspensions as intratympanic injection because the lipophilicity of drugs can affect their permeation of the round window membrane, an important pathway from the middle ear to the cochlea.Results: Three types of dexamethasone nanosuspensions were prepared; the dexamethasone nanocrystals in the three nanosuspensions were between approximately 250 and 350 nm in size. In order to compare the efficiency of Dex-SP and a dexamethasone nanosuspension in delivering dexamethasone to the inner ear, the concentrations of dexamethasone in perilymph and cochlear tissues were compared by liquid chromatography–mass spectrometry. The dexamethasone nanosuspensions showed significantly higher drug concentrations in perilymph and cochlear tissue than Dex-SP at 6 h; interestingly, animals treated with a nanosuspension showed a 26-fold higher dexamethasone concentration in the cochlear tissue than the Dex-SP group. In addition, the dexamethasone nanosuspension achieved better glucocorticoid receptor phosphorylation than Dex-SP both in vitro and in vivo, and in the ototoxic animal model, it showed a significantly better hearing protective effect than Dex-SP against ototoxic drugs. In safety evaluation, the nanosuspension showed no toxicity at concentrations up to 20 mg/mL in an in vivo test.Conclusions: A nanosuspension of dexamethasone was able to deliver dexamethasone to the cochlea very safely and efficiently and showed potential as a formula for intratympanic injection. In addition, it can be applied in studies on the delivery of various hydrophobic antioxidants to treat acute hearing loss.

scholarly journals Noise Induced Hearing Loss: A Case Study from a Speech-Language Pathologist’s Perspective

2021 ◽  
Author(s):  
Alejandro Brice
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Hearing Aids ◽  
Noise Exposure ◽  
Chronic Health Condition ◽  
Noise Induced Hearing Loss ◽  
Speech Language Pathologist ◽  
The Individual ◽  
The U.S

Hearing loss is very common in the United States and the most widespread disability in the U.S. Hearing loss is the third most chronic health condition in the U.S. Noise induced hearing loss (NIHL) results from damaging external noise. This injury leads to temporarily or permanently affecting sensitive inner ear structures (e.g., cochlea, organ of Corti, and hair cells). NIHL can result from a single high-level noise exposure or repeated exposures to excessively loud noises [i.e., typically 85 dBA or greater, (A weighted decibel)]. Damage to the inner ear can also result from aging (i.e., presbycusis). This case study documents the hearing loss of an otherwise healthy 21-year-old, male individual and his progressive moderate-to-severe sensorineural hearing loss over a period of 41 years. His history will be reported along with his perspective as a speech-language pathologist and speech scientist. The individual with hearing loss has adapted to wearing hearing aids over the last five years. Issues that have occurred affecting comprehension along with compensatory strategies that assisted listening and comprehension will be discussed.

scholarly journals Genetics of Peripheral Vestibular Dysfunction: Lessons from Mutant Mouse Strains

2014 ◽  
Vol 25 (03) ◽  
pp. 289-301 ◽  
Author(s):  
Sherri M. Jones ◽  
Timothy A. Jones
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Mouse Models ◽  
Noise Exposure ◽  
Mutant Mouse ◽  
Vestibular Dysfunction ◽  
Mouse Strains ◽  
Neural Function ◽  
Hereditary Hearing Loss ◽  
New Genes

Background: A considerable amount of research has been published about genetic hearing impairment. Fifty to sixty percent of hearing loss is thought to have a genetic cause. Genes may also play a significant role in acquired hearing loss due to aging, noise exposure, or ototoxic medications. Between 1995 and 2012, over 100 causative genes have been identified for syndromic and nonsyndromic forms of hereditary hearing loss. Mouse models have been extremely valuable in facilitating the discovery of hearing loss genes and in understanding inner ear pathology due to genetic mutations or elucidating fundamental mechanisms of inner ear development. Purpose: Whereas much is being learned about hereditary hearing loss and the genetics of cochlear disorders, relatively little is known about the role genes may play in peripheral vestibular impairment. Here we review the literature with regard to genetics of vestibular dysfunction and discuss what we have learned from studies using mutant mouse models and direct measures of peripheral vestibular neural function. Results: Several genes are considered that when mutated lead to varying degrees of inner ear vestibular dysfunction due to deficits in otoconia, stereocilia, hair cells, or neurons. Behavior often does not reveal the inner ear deficit. Many of the examples presented are also known to cause human disorders. Conclusions: Knowledge regarding the roles of particular genes in the operation of the vestibular sensory apparatus is growing, and it is clear that gene products co-expressed in the cochlea and vestibule may play different roles in the respective end organs. The discovery of new genes mediating critical inner ear vestibular function carries the promise of new strategies in diagnosing, treating, and managing patients as well as predicting the course and level of morbidity in human vestibular disease.

scholarly journals Impact of Hearing Loss and Amplification on Performance on a Cognitive Screening Test

2018 ◽  
Vol 29 (07) ◽  
pp. 648-655 ◽  
Author(s):  
Gabrielle H. Saunders ◽  
Ian Odgear ◽  
Anna Cosgrove ◽  
Melissa T. Frederick
Keyword(s):  
Hearing Loss ◽  
Hearing Impairment ◽  
Hearing Aids ◽  
Pure Tone ◽  
Pure Tone Audiometry ◽  
Cognitive Screening ◽  
Strong Correlations ◽  
Speech In Noise ◽  
Hearing Ability ◽  
The Individual

AbstractThere have been numerous recent reports on the association between hearing impairment and cognitive function, such that the cognition of adults with hearing loss is poorer relative to the cognition of adults with normal hearing (NH), even when amplification is used. However, it is not clear the extent to which this is testing artifact due to the individual with hearing loss being unable to accurately hear the test stimuli.The primary purpose of this study was to examine whether use of amplification during cognitive screening with the Montreal Cognitive Assessment (MoCA) improves performance on the MoCA. Secondarily, we investigated the effects of hearing ability on MoCA performance, by comparing the performance of individuals with and without hearing impairment.Participants were 42 individuals with hearing impairment and 19 individuals with NH. Of the individuals with hearing impairment, 22 routinely used hearing aids; 20 did not use hearing aids.Following a written informec consent process, all participants completed pure tone audiometry, speech testing in quiet (Maryland consonant-nucleus-consonant [CNC] words) and in noise (Quick Speech in Noise [QuickSIN] test), and the MoCA. The speech testing and MoCA were completed twice. Individuals with hearing impairment completed testing once unaided and once with amplification, whereas individuals with NH completed unaided testing twice.The individuals with hearing impairment performed significantly less well on the MoCA than those without hearing impairment for unaided testing, and the use of amplification did not significantly change performance. This is despite the finding that amplification significantly improved the performance of the hearing aid users on the measures of speech in quiet and speech in noise. Furthermore, there were strong correlations between MoCA score and the four frequency pure tone average, Maryland CNC score and QuickSIN, which remain moderate to strong when the analyses were adjusted for age.It is concluded that the individuals with hearing loss here performed less well on the MoCA than individuals with NH and that the use of amplification did not compensate for this performance deficit. Nonetheless, this should not be taken to suggest the use of amplification during testing is unnecessary because it might be that other unmeasured factors, such as effort required to perform or fatigue, were decreased with the use of amplification.

scholarly journals Identification and Discrimination of Sound Textures in Hearing-Impaired and Older Listeners

2021 ◽  
Vol 25 ◽  
pp. 233121652110656
Author(s):  
Oliver Scheuregger ◽  
Jens Hjortkjær ◽  
Torsten Dau
Keyword(s):  
Hearing Loss ◽  
Hearing Impairment ◽  
Broad Class ◽  
Temporal Structure ◽  
Discrimination Performance ◽  
Hearing Impaired ◽  
Sensorineural Hearing ◽  
Identification Accuracy ◽  
Texture Discrimination ◽  
The Individual

Sound textures are a broad class of sounds defined by their homogeneous temporal structure. It has been suggested that sound texture perception is mediated by time-averaged summary statistics measured from early stages of the auditory system. The ability of young normal-hearing (NH) listeners to identify synthetic sound textures increases as the statistics of the synthetic texture approach those of its real-world counterpart. In sound texture discrimination, young NH listeners utilize the fine temporal stimulus information for short-duration stimuli, whereas they switch to a time-averaged statistical representation as the stimulus’ duration increases. The present study investigated how younger and older listeners with a sensorineural hearing impairment perform in the corresponding texture identification and discrimination tasks in which the stimuli were amplified to compensate for the individual listeners’ loss of audibility. In both hearing impaired (HI) listeners and NH controls, sound texture identification performance increased as the number of statistics imposed during the synthesis stage increased, but hearing impairment was accompanied by a significant reduction in overall identification accuracy. Sound texture discrimination performance was measured across listener groups categorized by age and hearing loss. Sound texture discrimination performance was unaffected by hearing loss at all excerpt durations. The older listeners’ sound texture and exemplar discrimination performance decreased for signals of short excerpt duration, with older HI listeners performing better than older NH listeners. The results suggest that the time-averaged statistic representations of sound textures provide listeners with cues which are robust to the effects of age and sensorineural hearing loss.

Hyaluronan as a propellant for epithelial movement: the development of semicircular canals in the inner ear of Xenopus

Development ◽  
1991 ◽  
Vol 112 (2) ◽  
pp. 541-550 ◽  
Author(s):  
C.M. Haddon ◽  
J.H. Lewis
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Inner Ear ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Otic Vesicle ◽  
Membranous Labyrinth ◽  
The Core ◽  
Secondary Palate

The membranous labyrinth of the inner ear, with its three semicircular canals, originates from a simple spheroidal otic vesicle. The process is easily observed in Xenopus. The vesicle develops three dorsal outpocketings; from the two opposite faces of each outpocketing pillars of tissue are protruded into the lumen; and these paired ‘axial protrusions’ eventually meet and fuse, to form a column of tissue spanning the lumen of the outpocketing like the hub of a wheel, with a tube of epithelium forming the semicircular canal around the periphery. Each axial protrusion consists of epithelium encasing a core of largely cell-free extracellular matrix that stains strongly with alcian blue. In sections, at least 60% of the stainable material is removed by treatment with Streptomyces hyaluronidase. When Streptomyces hyaluronidase is microinjected into the core of a protrusion in vivo, the protrusion collapses and the corresponding semicircular canal fails to form. Hyaluronan (hyaluronic acid) in the core of the protrusion therefore seems to be essential in driving the extension of the protrusion. Autoradiography with tritiated glucosamine indicates that the hyaluronan-rich matrix is synthesised by the epithelium covering the tip of the protrusion; the basal lamina here appears to be discontinuous. These findings indicate that the epithelium of the axial protrusion propels itself into the lumen of the otocyst by localised synthesis of hyaluronan. Hyaluronan may be used in a similar way in the development of other organs, such as the heart and the secondary palate.

scholarly journals Histone demethylase KDM4B regulates otic vesicle invagination via epigenetic control of Dlx3 expression

2015 ◽  
Vol 211 (4) ◽  
pp. 815-827 ◽  
Author(s):  
Rosa A. Uribe ◽  
Ailín L. Buzzi ◽  
Marianne E. Bronner ◽  
Pablo H. Strobl-Mazzulla
Keyword(s):  
Inner Ear ◽  
Histone Methylation ◽  
Chromatin Immunoprecipitation ◽  
Morphological Changes ◽  
Critical Role ◽  
Histone Demethylase ◽  
Otic Vesicle ◽  
Direct Target ◽  
Otic Placode

In vertebrates, the inner ear arises from the otic placode, a thickened swathe of ectoderm that invaginates to form the otic vesicle. We report that histone demethylase KDM4B is dynamically expressed during early stages of chick inner ear formation. A loss of KDM4B results in defective invagination and striking morphological changes in the otic epithelium, characterized by abnormal localization of adhesion and cytoskeletal molecules and reduced expression of several inner ear markers, including Dlx3. In vivo chromatin immunoprecipitation reveals direct and dynamic occupancy of KDM4B and its target, H3K9me3, at regulatory regions of the Dlx3 locus. Accordingly, coelectroporations of DLX3 or KDM4B encoding constructs, but not a catalytically dead mutant of KDM4B, rescue the ear invagination phenotype caused by KDM4B knockdown. Moreover, a loss of DLX3 phenocopies a loss of KDM4B. Collectively, our findings suggest that KDM4B play a critical role during inner ear invagination via modulating histone methylation of the direct target Dlx3.

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